Revert "the event.which property normalizes event.keyCode and event.charCode. It is recommended to watch event.which for keyboard key input. related #37 http://api.jquery.com/event.which/"

This reverts commit 89fc2bcaca57f7dfcc39667310ca60e4d1d2c84c.
trying to fix left arrow/% case in firefox. related #37 #53